*For fitting to both sides of glass before it is sandwiched between the porthole frames*Available in either 1.6 or 3.2 mm thickness to suit varying door and glass thicknessesâ€¢For timber fire rated doors*In the event of fire, the tape starts to intumesce at 176°C expanding 6-8 times its volume ensuring the integrity of the door and porthole frame*With PSA backing1.6 x 9.5 mm